Simuling w pre-rigged microtraxes

I was thinking a bit this morning -- If you're simulclimbing with microtraxes prerigged on the rope (and clipped to your belay loop), if the teeth accidentally engage before you place the trax and then you whip (god forbid) -- you're taking a fall onto a toothed device, yeah? That seems very bad, especially because a simul leader fall is likely massive -- I have to think that the rope would be cut.

I'm not saying simul climbing is at all safe or that you should ever fall, but I find it curious that what I've observed to be common practice while simulclimbing might destroy whatever semblance of a safety net you have -- it's really not so hard to knock a trax and get the teeth to drop.

Is this reasoning correct? If so, what do you all do when simuling in situations where you can't always get a no-hands to rig a trax, and need to pre-rig?

Yeah yeah I know, YGD.

Wouldn't the microtraxion be rigged the "other way"? In other words wouldn't it let rope feed through to lengthen a leader fall? So no additional stress on the rope if the leader whips.

My thought was that the trax is rigged so that if the second falls, it clamps and the rope doesn't go anywhere. If you still had the trax on your harness and fell, the force would come from the far side of the rope -- the direction that the trax does not permit (if the teeth are engaged).

Could be confused, though.

Isaiah aka Zay Foulks wrote:

Yeah I just climb with the traxions racked on my harness with the rest of my gear. 

Are you trying to save time by having them pre-rigged on your belay loop?

More so for when the climbing is steep enough that you can't really rig with one hand

Jack Neuswrote:

My thought was that the trax is rigged so that if the second falls, it clamps and the rope doesn't go anywhere. If you still had the trax on your harness and fell, the force would come from the far side of the rope -- the direction that the trax does not permit (if the teeth are engaged).

Could be confused, though.

Ok, I think I understand what you're saying. The cam is engaged and somehow enough rope has gotten pulled through the microtraxion so there's a loop of slack rope between your harness and the microtraxion. As you climb up you're essentially pulling the rope up by the microtraxion and not your tie-in.

If you can't rig it (one handed or not), should you really be simuling it? You can also always clip in direct to a piece. 

At the same time, would taking a lead fall actually core shot a rope enough to completely sever it? I've only heard about that happening when ropes run over sharp edges.

One possible solution to this problem would be to have the microtrax not clipped to your belay loop. Perhaps hang it on the end of a draw, and the top of the draw is clipped to either a chest harness or a sling over your shoulder? The draw should keep the trax up by your knot, and in a fall the whole mess could ride up.

Why is the traxion on your belay loop while leading? While simul climbing don’t you place the trax on a bolt or solid piece so it allows the leader to climb and pull rope up through the device but protects the leader in the event that the follower falls?  

I’m having a hard time understanding the OP’s set up and why it would be on the belay loop?   Is he confusing or conflating simul climbing and short fixing?

If you pre rig the trax, which is normal as it means one can load two without risk of dropping them, don't clip it to the belay loop. Clip it to a loop of 1mm tied to the belay loop, or just about anything. 

The 1mm should snap rather than the rope being trashed. 

To meet its CE criteria, the microtraxion has to hold up to 4kN without damaging the rope. Beyond that, rope damage can occur. If memory serves, toothed devices tend to abrade the sheath, core shot the rope, and/or fully rupture the sheath as loads increase, while non-toothed devices tend to break the rope completely by pinching it.

4kN is a pretty large (but certainly not impossible) load on the climber for a lead fall. Whether that might be generated in the falls in question here will depend on rope drag, length of fall, amount of rope in service, how clean the fall is (i.e. will the leader hit a ledge before loading the rope? I'm presuming steep terrain in this context, though), etc. I'd wager that for many falls, the load would stay below the 4kN threshold. The leader could certainly bump the button on the microtrax, but presumably would have it locked open at least initially. Maybe combine this with a cut resistant rope like Edelrid is making now, and even above 4kN things look relatively "safe" at least as far as shredding the rope is concerned. However, with the sheath potentially shredded, the rope could cut on an edge much more readily.

An additional layer of security could be a properly oriented overhand slip knot below the microtrax. I've not pre-rigged the microtrax in this way before as I often just take a quick belay from the follower if I'm in cruxy terrain, and then place the microtrax after the crux. In other words, I've definitely not tested this idea in any real way. Playing with a rope and a microtrax hanging on my belay loop just now, I think the slip knot could work. I think this is more a speed climbing technique than general simul-climbing anyway, since I can get that quick belay from the follower in most cases. The slip knot only woks with a single pre-rigged microtrax, though; an additional microtrax requires an additional slip knot, and that will makes things get crowded quickly on the belay loop.

Just another idea to consider.

The obvious solution is to have it locked open... Is there some problem with that?  It's easy enough to engage it with one hand after you place it.

Derek DeBruinwrote:

An additional layer of security could be a properly oriented overhand slip knot below the microtrax. 

Having used pre-rigged microtraxions and realizing the same thing (I.e., whipping onto the teeth), I think this is probably the best solution. A correctly oriented slip not in front of the each micro on a locker to your belay loop, so you are essentially “tying in short” to a locker in front of the micro. Should probably be east enough to unclip and pop the slipknot one-handed. I haven’t tried this yet, but seems like a good idea! 

Kevin Mokracekwrote:

Why is the traxion on your belay loop while leading? While simul climbing don’t you place the trax on a bolt or solid piece so it allows the leader to climb and pull rope up through the device but protects the leader in the event that the follower falls?  

I’m having a hard time understanding the OP’s set up and why it would be on the belay loop?   Is he confusing or conflating simul climbing and short fixing?

My understanding is that there are two uses: simul climbing and short fixing. For simul climbing the device is on the follower's harness and is rigged so it will lock if either the leader or the followers falls. For short fixing it is attached to an anchor and is rigged so the leader can move up but it will lock if the followers falls. Rigged this way, there will be no slack between the leader and the follower. Can someone please confirm my understanding?

By the way, I use a Petzyl Shunt or Kong Duck device, which both have ribs that don't damage the rope.

Thanks for the tips, everyone!

I'll have to experiment with the slip knots. Using 1mm cord as a screamer is a really neat idea, my only thought there is that if you have drag and are tugging on your follower (maybe if you're short on rope but need to get to a good stance) the cord might break prematurely.

Could leave the micro engaged on the rope just below your tie in, but not clipped to the belay loop. Would probably be super annoying though.

wouldn't the micro just fall/slide down the rope, assuming this is the leader we're talking about?

tried it, it slides right down the rope. Not sure what I'm missing here...

to stop a follower fall, the rope must be able to run free *up* through the device. Thus, alternatively, the device can simply slide down the rope, if it's not restrained to something, as the previous poster suggested. seriously, what am I missing?

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Edit since i'm overposted:

I felt it was obvious enough that I was replying to jack's suggestion, in the post directly above my initial response and didn't need to quote post... but obviously not.

The micro def holds on a 9mm rope...but starts sliding down as soon as you shake the rope, which would clearly be happening, thus it would simply slide down withOUT the 1mm cord, per jack's suggestion.

@Christian and Artem:

Ya'll are both right, just talking past each other. Christian is talking about Jack Lange's suggestion, and is correct that the microtrax could slide down the rope if the spring on the cam doesn't provide enough force to grip a skinny rope and the microtrax isn't clipped to something (though I just gave that a whirl and didn't have a problem with the cam teeth gripping the rope). More to the point, if you lock the cam open so there's no progress capture (which is the whole concern here), the microtrax absolutely just slides down the rope if it isn't secured to the belay loop. But Artem's post and diagram correctly demonstrate what you want to do with the microtrax when placing it on protection to secure the leader against a follower fall.

Derek DeBruinwrote:

 while non-toothed devices tend to break the rope completely by pinching it.

Wait, really?  When simu following, I have often left the rope in my auto locking belay device on my belay loop and coil the extra role kiwi style, always figuring that the belay device would engage in a fall (god forbid, and considering that when simuling I consider it a "you must not fall" condition, especially for the follower). But your saying it would likely cut the rope?  I've never heard of that.  Also not sure I believe you because auto locking belay devices don't engage all the way (at least the Mad Rock lifeguard I have stops with 3.5mm of space remaining between the cam and the plate).

Damn, I'm definitely gonna die if you are right.

Nico Wrightwrote:

Wait, really?  When simu following, I have often left the rope in my auto locking belay device on my belay loop and coil the extra role kiwi style, always figuring that the belay device would engage in a fall (god forbid, and considering that when simuling I consider it a "you must not fall" condition, especially for the follower). But your saying it would likely cut the rope?  I've never heard of that.  Also not sure I believe you because auto locking belay devices don't engage all the way (at least the Mad Rock lifeguard I have stops with 3.5mm of space remaining between the cam and the plate).

Damn, I'm definitely gonna die if you are right.

A clarification: by "device" I mean progress capture pulley or similar, not belay device. I rig a grigri in front of my coils regularly for simul-climbing, so I don't consider it a significant concern. I'm not sure what the rope cutting force would be with a grigri, but I'm sure it's plenty high (maybe in the double digits kN, but definitely speculating).

Keep in mind that none of this is relevant if the force is less than 4kN. As the follower in a simul system, you are very unlikely to experience 4kN whether you fall or the leader falls. If you're using a grigri on the leader end of things, plenty of folks have lead rope soloed on a grigri and survived the whip. The bigger concern if running a grigri as the simul leader is the follower fall, which could pull the leader quite violently into the gear below (unless of course they've placed one of those microtraxions that they pre-rigged). That's unlikely to generate enough force to matter, but it could jam the grigri open, and that might let enough rope through to tighten the coils and cause respiratory system trauma of one kind or another.